The Enterprise uniforms were the first ones that looked really believable. I loved how the Kelvin uniforms in STXI are a stylized halfway between ENT and TOS, and the STXI nuTOS are my favourite at the moment.
IMO the TMP, TNG, VOY and DS9 gear are PJ's, or variations of PJ's
. TWoK gear looks too Mountie-like for my tastes. FC looks like smart funeral winter PJ's.
All-time worst looking gear? The alternate futures of "All Good Things" and "Endgame". Worst fugly PJ's ever. Bizarrely these are very similar to the far-superior Kelvin uniforms. I guess that's the difference a big budget makes.